Melting process for recovering bitumens from the earth



June 29, 1965 w. s. MILLER 3,191,679

MELTING PROCESS FOR RECOVERING BITUMENS FROM THE EARTH 9 34 Q9 30 23 25N I I I3 2 H I 20 l i I '26 l I 32 I i -|s I l I l l4 9 i=1 Znl OriginalFiled April 13. 1961 way/ W )Wf INVENTOR. mNDELL 5. MILLER United StatesPatent C) 3,191,579 MELTING PROCESS 1 6R RECQVERING EITUMENS FROM THEEARTH Wendell S. Miller, 1341 (lornstoclr Ave., Los Angeies 24, Calif.

Original application Apr. 13, 1961, Ser. No. 113,577, new Patent No.3,131,914, dated May 5, 1964. Divided and this application Apr. 20,1964, Ser. No. 360,961

2 Claims. (Cl. 166-39) This application is a division of my co-pendingapplication Serial No. 113,577, filed Apr. 13, 1961, now Patent No.3,131,914.

This invention relates to an improved process for recovering from theearth certain meltable and combustible bitumens of the character ofGilsonite, grahamite, tar and the like.

As is well known, there are numerous deposits of Gilsonite and grahamiteat various points in the earth, which are actually relatively rich inthese substances, but which are in some Ways so positioned in the earthas to render it impossible to mine these deposits by conven tionalmethods. In many instances, these bitumens are found in very narrow orthin vertically extending veins, which may extend downwardly into theearth to a very substantial depth, but which are too narrow to dig oututilizing conventional mining equipment. The general object of thepresent invention is to provide a process which is capable of recoveringfrom the earth the above discussed substances, which heretofore couldnot be mined efiectively. As will appear, the present process may beutilized with a minimum of expense to bring bitumens to the surface ofthe earth in a form essentially ree of other substances.

In performing the process of the invention, the bitumen is converted toa condition in which it is easily recoverable from a location deepwithin the earth, with the conversion being effected very uniquely byactually burning a portion of the material in the earth. This burning ofsome of the substances itself produces heat in the earth, which acts tomelt additional portions of the surrounding-bitumen, so that thismaterial may then be easily withdrawn upwardly to the surface of theearth in molten freefiowing condition. In the simplest variation of theinvention, the molten material is pumped upwardly by the pressure of thegases of combustion produced by the burning operation itself.

The above and other features and objects of the present invention willbe better understood from the following detailed description of thetypical embodiments illustrated in the accompanying drawings in which:

FIG. 1 is a vertical section through a first type of apparatus forrecovering an earth substance in molten form;

FIG. 2 shows an arrangement similar to FIG. 1, but in which theapparatus extends downwardly to the production zone at an inclinationand through an adjacent formation of less readily meltable material thanis being produced from the mine.

In FIG. 1, I have represented at 19 a body or a layer of materialsspaced beneath the surface 11 of the earth, and containing a substanceto be recovered. This body 10 may typically consist of Gilsonite,grahamite or other similar bitumens. Above the body 19, there isillustrated in FIG. 1 an over-burden or upper strata 12. This layer 12may in most instances be formed of a material or materials having amelting temperature well above the melting temperature of the substanceto be recovered from layer 19.

In recovering the material from body 1% by the apparatus of FIG. 1, thefirst step is to drill into the earth a hole or bore 13, which mayinitially be of a uniform diameter through the entire vertical distancefrom the surface of the earth 11 down to the bottom 14 of the hole. InFIG. 1, the lower portion of this bore as originally drilled isrepresented in broken lines at 15. After bore 13 has been drilled intothe earth, there are installed in this bore two desirably concentricpipes 16 and 17, with the former being disposed about the latter toprovide an annular vertically extending passage 18 between the pipes. Aswill be understood, each of these pipes 1d and 17 will in most cases beformed of a series of separate sections or stands, threadedly joinedtogether in an end-to-end series to form overall pipe assemblies ofproper lengths to reach the producing formation. The inner pipe 17extends downwardly to a location 19 spaced but a short distance abovethe bottom 14 of the bore. The outer pipe 16, on the other hand,terminates at a point 20, spaced well above the lower end 19 of pipe 17.The upper end of annular passage 18 about pipe 17 is suitably sealed orclosed by conventional well head apparatus of any desirable type, asrepresented by the seal diagrammatically represented at 21 in FIG. 1. Agas containing oxygen is fed into the upper end of annular space 18through a titting represented at 22, and from a source of such gas underpressure indicated at 23. This gas coming from source 23 may in someinstances be pure oxygen, and in other instances be air or anothermixture of gases containing oxygen and capable of supporting combustion.Source 23 preferably maintains a continuous flow of such combustionsupporting gas downwardly through passage 18, to emit continuously fromthe lower end 20 of pipe 16. This rate of oxygen feed to the productionzone may be great enough to support combustion of the material in body10 continuously. Molten production fluid flows upwardly through innerpipe 17, and discharges from the upper end of that pipe through a line2-4 leading to an accumulation tank 25.

In conjunction with the apparatus thus far described, there is alsoprovided some means for initiating combustion of the productionsubstance near the lower end of pipe 16. This means for starting thecombustion may be simply a mass of burning Thermit or other materialinjected into the upper end of annular space 18 to fall downwardly therethrough to the production zone, or may be any other convenient type ofigniting system. In FIG. 1, I have typically represented an arrangementin which there is provided about inner pipe 17 at a location directlybelow the lower end 2% of pipe 16, an annular mass 26 of highlycombustible material, typically Thermite, which is ignited electricallyby current fed to body 26 through wires 27 extending upwardly to thesurface of the earth. These wires connect at the surface of the earth toa power source 23, through a switch 29 whose closure fires thecombustible charge 26.

Assuming that the bore 13 has been drilled downwardly to location 14(with the bore being of a uniform diameter for its entire length), andassuming that all of the apparatus illustrated in FIG. 1 is in positionas shown, the first step in placing the apparatus in operation may be toactuate the air or oxygen source 23 to commence a flow of air or oxygendownwardly through passage 18, and then upwardly through pipe 17 and totank 25. This tank 25 may have an upper vent 31 through which air orgases or combustion in the upper portion of the tank may escape to theatmosphere, leaving any production liquid which comes upwardly throughpipe 17 in the tank. After the air or oxygen flow has been commenced,the operator closes switch 29 to fire combustible charge 2%. This chargeis designed to raise the temperature of the portion of body 10 which isdisposed directly adjacent the lower end of pipe 1 5 to a value causingthe combustible Gilsonite, grahamite, or the like to burn. The rate ofoxygen delivery through passage 18 is maintained at a value such as tocontinue this burning even arouses after charge 26 is gone, and as longas it is desired to continue the production from zone 1! The heat ofcombustion is high enough to melt a large amount of the G-ilsonite,grahamite, or the like forming the wall of bore 13, so that this moltenmaterial falls downwardly to the bottom of bore 13, as represented at31. The burning action progressively enlarges the lower portion of thebore to form a cavity 32 considerably larger in diameter than the upperportion of bore 13. Preferably, most of the burning takes place in theupper portion of cavity 32.

The molten material 31 which falls to the bottom of the cavity is forcedupwardly through pipe 17 by the pres.- sure of the gases of combustionresulting from burning operation. This molten material flows into tank25, and any air and other gases mixed with the molten material is ventedoff to the atmosphere through vent 30. If the pumping action reaches apoint where all of the liquid 31 has been removed from the bottom of thecavity, then the gases of combustion flow upwardly through pipe 17 andto the atmosphere without intermixed liquid until additional moltenmaterial accumulates in the bottom of the cavity, at which time theliquid pumping action recommences automatically. It is also noted thatthe pressure of upper stratum 12 above lower body 10 effectivelyprevents the upward advancement of the burning or melting action beyondthe interface 33 between the two strata, since it is assumed that layer12 is not readily combustible or meltable.

There may be provided in the line leading from oxygen or air source 23to passage 18 a variable passage throttle valve 34, which is capable ofregulatingthe rate of air or oxygen delivery, andthereby varying thetemperature maintained in the cavity 32. This temperature is maintainedat a value sufficiently above the melting temperature of the substancebeing produced to assure arrival of the substance in molten readilyflowable conditionin tank 25. For this purpose, the temperature may beregulated either by reference to a reading produced at the surface ofthe earth by a temperature responsive element located within cavity 32,or by merely noting the condition of the produced substance as itreaches tank 25.

FIG. 2 shows an arrangement which may be considered identical with thatof FIG. 1, except that the bore 52 through which pipes 53 and 54 extenddownwardly is disposed at an angle such that it first passes througharelatively non-inflammable and non-meltable formation 55, and thenenters the combustible and meltable formation 56 (typically of Gilsoniteor grahamite) at a location spaced beneath the surface of the earth. Airor oxygen is fed to the burning zone from a source 57 and through theouter passage between pipes 53 and 54, while the production fluid ispumped upwardly through the inner pipe by the pressure of the gases ofcombustion. The arrangement of FIG. 2 is particularly useful where theformation 56 takes the form of a very thin or narrow vertical vein ofGilsonite or the like, extending upwardly to the surface of the earth,so that if the pipes extended vertically through that vein to thesurface, the heat of the pipes might cause melting of the material aboutthe pipes, and the resultant formation of a leakage space about thepipes. Since the pipes of FIG. 2 pass through formation 55 which isessentially incombustible, and which melts at a higher temperature thanmaterial 56, there is no danger of melting the material about pipe 54 bythe heat of that pipe, so that the discussed leakage gap cannot bedeveloped.

I claim:

1. The process for removing from the earth a combustible and meltablesolid bitumen emplaced in a formation in which a bituminous stratumcommunicates with the surface of the earth and adjoins a secondnoncombustible and infusible formation, comprising the steps ofproducing in said second formation a bore hole communication with saidbituminous formation at a point remote from the surface of the earth andsufficiently remote from the said bituminous formation near the surfaceof the earth to provide thermal isolation of said formation from saidbore hole, inserting in said bore hole conduit means communicating withsaid bituminous formation at a point remote from the surface of theearth, supplying oxidizing gas to said formation at a point remote fromthe surface of the earth, igniting bitumen in said bituminous formationinto in situ combustion with said oxidizing gas, melting portions ofsaid bitumen by means of the heat produced by said in situ combustion,removing said melted bitumen through said conduit by means of the gasesproduced by said combustion.

2. The process for removing a combustible and meltable solid bitumenfrom a nearly vertically standing formation of said bitumen adjacent anincombustible and infusible solid formation, comprising the steps ofslant drilling a bore hole through said incombustible formation intocommunication with said bituminous formation at a point remote from theupper end thereof, supplying oxidizing gas to said bituminous formationthrough said bore hole, igniting said bitumen into com bustion with saidoxidizing gas in situ, melting portions of said bitumen by means of theheat of said in situ combustion removing said melting porions of bitumenby a path sufficiently remote and thermally isolated from saidbituminous formation near the upper end thereof to prevent the directcommunication of said in situ combustion with the surface of the earthalong said path.

References Cited by the Examiner UNITED STATES PATENTS 531,787 1/95Dubbs.

BENJAMIN HERSH, Primary Examiner.

1. THE PROCESS FOR REMOVING FROM THE EARTH A COMBUSTIBLE AND MELTABLESOLID BITUMEN EMPLACED IN A FORMATION IN WHICH A BITUMINOUS STRATUMCOMMUNICATES WITH THE SURFACE OF THE EARTH AND ADJOINS A SECONDNONCOMBUSTIBLE AND INFUSIBLE FORMATION, COMPRISING THE STEPS OFPRODUCING IN SAID SECOND FORMATION A BORE HOLE COMMUNICATION WITH SAIDBITUMINOUS FORMATION AT A POINT REMOTE FROM THE SURFACE OF THE EARTH ANDSUFFICIENTLY REMOTE FROM THE SAID BITUMINOUS FORMATION NEAR THE SURFACEOF THE EARTH TO PROVIDE THERMAL ISOLATION OF SAID FORMATION FROM SAIDBORE HOLE, INSERTING IN SAID BORE HOLE CONDUIT MEANS COMMUNICATING WITHSAID BITUMINOUS FORMATION AT A POINT REMOTE FROM THE SURFACE OF THEEARTH, SUPPLYING OXIDIZING GAS TO SAID FORMATION AT A POINT REMOTE FROMTHE SURFACE OF THE EARTH, IGNITING BITUMEN IN SAID BITUMINOUS FORMATIONINTO IN SITU COMBUSTION WITH SAID OXIDIZING GAS, MELTING PORTIONS OFSAID